Investors Press Yahoo on Compensation After No. 2's Exit

Effort Marks a Challenge to CEO Marissa Mayer

A small group of investors are pressuring Yahoo Inc. to revise its approach to hiring and compensation following Chief Executive Marissa Mayer's expensive firing of her No. 2 executive.

CtW Investment Group, an arm of labor federation Change to Win, called on Yahoo to take steps to ensure it won't overpay for executive talent, citing ousted chief operating officer Henrique de Castro's estimated compensation of $109 million for just...